Brown beef and onion; drain, Add tomato sauce, 1 can water, taco seasoning mix and olives, Place crescent rolls in long oblong pan, pressing to form crust, Sprinkle 1/2 of corn chips over bottom crust, Next, spread meat mixture, then sour cream over meat mixture, Add shredded cheese next; place remaining corn chips on top,______, Serve in squares, topped with lettuce, tomato and avocado slices,